Deterministic spin-orbit torque switching via structural engineering*

Current-induced spin-orbit torque (SOT) can be employed to control magnetization in magnetic random-access memory (MRAM) with perpendicular magnetic anisotropy (PMA), but typically requires an applied in-plane magnetic field. To eliminate the need of this applied field and achieve better on-chip memory designs, we deposite 4d transition metal Mo in a canted way as the SOT source. Although the spin-orbit interaction in Mo is weaker than in 5d metals such as Pt, W, or Ta, deterministic switching can still be achieved. This result suggests that growth configuration can play a more important role than material selection in some cases, which could really impact the engineering of next-generation field-free SOT-MRAM.